ISSN:0263-0257    

DOI:10.1080/02630259108970598

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The Energy Management and Maintenance Analysis (EMMA) model was developed and is used at Manitoba Hydro to support the decision making process of planning the system operation. It is a flexible linear programming based optimization tool capable of handling various problems in the system operations planning (long, medium and short-term planning). At the University of Manitoba research is under way to investigate the possible improvement of the model performance by applying an alternative linearization procedure for the hydro energy relationship known as ‘successive linear programming’. The alternative model, named Energy Management by Successive Linear Programming (EMSLP), developed at the University, has shown some advantages over the original EMMA model. This paper addresses the practical role of EMMA in the current Manitoba Hydro system operation and the research need for its potential improvement. The strong link which exists between the experience gained in practice and the research potential available at the Civil Engineering Department of the University will be discussed.

ISSN:0263-0257    

DOI:10.1080/02630259108970599

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The drive to develop expert systems is forcing would-be developers to examine and make explicit the mental processes which experts use. Much of what an expert actually does is carried out intuitively and without any conscious thought. The procedures and mental processes used in civil engineering design involve a ‘creative phase’, where the design first takes shape and then ‘evolves’, and a ‘checking phase’ to ensure that it will be satisfactory. Experience and judgement play large roles in both phases. In this paper, the role of experience and how it is gained are examined. Defining experience is important not only for expert systems designers but also for the education and training of future design engineers.

ISSN:0263-0257    

DOI:10.1080/02630259108970600

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Issues involved in the knowledge acquisition process for engineering applications of expert systems are discussed, with reference to a project underway in the reservoir management domain. Since there are no well established guidelines for the crucial task of acquiring human problem solving expertise, the individual responsible forthis task must rely on his own judgement and suggestions found in the literature. Based on the experience from this project, success in the area of knowledge acquisition appears to require the incremental development of very problem specific engineering expert systems, which facilitates the knowledge acquisition process. Other important factors described include the domain knowledge of the knowledge engineer (the person responsible for knowledge acquisition), the interaction between the expert and the knowledge engineer, and the expectations for the expert systems.

ISSN:0263-0257    

DOI:10.1080/02630259108970601

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper presents a new method utilizing the Monte Carlo simulation technique for processing fuzzy information. The method was primarily developed for determining the weighted average of a group of ratings that are represented by fuzzy subsets. By generating a uniform random number, normalizing it with respect to the maximum functional value of the cumulative membership function, and then equating the normalized uniform random number to the cumulative function F(x), a value x can be back-calculated for each fuzzy subset. The resulting value x is a random number representing that fuzzy subset. The weighted average was then calculated with these random numbers. The first through fourth moment parameters were obtained and used to fit the random values of the weighted average with a beta distribution. By normalizing the curve-fitted beta distribution function with respect to its maximum functional value, the membership function of the final fuzzy subset was obtained. Comparison is made between the new method and the vertex method which provides an exact but discrete solution. The results show that the new method always yields a very good approximation in a significantly shorter computation time-as much as two orders of magnitude in some of the cases presented.

ISSN:0263-0257    

DOI:10.1080/02630259108970602

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The methods used in practice for realigning railway horizontal curves are based on trial and error. In this paper, a linear-integer optimization model that minimizes the absolute deviations between the realigned curve and an ideal curve is developed. The model includes constraints related to (1) the maximum allowable shifts of the railway track, (2) coincidence of the realigned and original tangents, and (3) equality of the central angles of the realigned and ideal curves. The model is extended to accommodate situations of spiralling an old curve (not originally spiralled) during realignment. Other realignment objectives such as minimization of the total track shifts and minimization of the maximum deviation are presented. The output of the model includes the required track shifts to realign the existing curve to a smoother curve. Application of the model is illustrated using real-world examples. This model, which is readily solved by existing computer software, should be valuable for railway engineers who are concerned with the safety and smooth-ride of railways.

ISSN:0263-0257    

DOI:10.1080/02630259108970603

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This study presents a methodology based on fuzzy set theory that enables the determination of a single Pavement Distress Index (PDI) from commonly used surface distresses. The magnitudes of individual distresses are established using linguistic scales. These have been formulated on the basis of pattern classification techniques that consider both the severity and the extent of each distress along nominal lengths of pavement structures. Linguistic distress values are represented by membership functions and are quantified using input from maintenance experts. A single measure of overall pavement damage is determined through fuzzy weighted average computations and linguistic approximation. The methodology is illustrated in a case study, and important conclusions are presented and discussed.

ISSN:0263-0257    

DOI:10.1080/02630259108970604

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper describes a bridge condition assessment model that is based upon the simplification of a computational technique called resolution identity of fuzzy sets. The proposed model utilizes a fuzzy weighted average to combine fuzzy bridge condition ratings. The procedure is based on the decomposition of fuzzy sets into non-fuzzy level-sets or intervals. The utility and effectiveness of this procedure are illustrated with an example of the bridge condition assessment problem.

ISSN:0263-0257    

DOI:10.1080/02630259108970605

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259108970606

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259108970607

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor